Use Scala 2.13.0 (#129)

Author: tsuyoshizawa

.travis.yml

@@ -2,7 +2,7 @@ language: scala
 scala:
   - 2.12.8
   - 2.11.12
-  - 2.13.0-RC1
+  - 2.13.0
 jdk:
   - oraclejdk8
   - openjdk11

build.sbt

@@ -1,5 +1,5 @@
 val commonDependenciesInTestScope = Seq(
-  "org.scalatest" %% "scalatest" % "3.0.8-RC2" % "test",
+  "org.scalatest" %% "scalatest" % "3.0.8" % "test",
   "ch.qos.logback" % "logback-classic" % "1.2.3" % "test"
 )
 
@@ -12,7 +12,7 @@ lazy val scalaOAuth2ProviderSettings =
     Seq(
       organization := "com.nulab-inc",
       scalaVersion := "2.12.8",
-      crossScalaVersions := Seq("2.12.8", "2.11.12", "2.13.0-RC1"),
+      crossScalaVersions := Seq("2.12.8", "2.11.12", "2.13.0"),
       scalacOptions ++= Seq("-deprecation", "-unchecked", "-feature"),
       scalacOptions ++= unusedWarnings,
       publishTo := {